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Straw amendments did not induce high N 2 O emissions in non‐frozen wintertime conditions: A study in northern Germany
Author(s) -
Wang Haitao,
Ma Shutan,
Dittert Klaus
Publication year - 2020
Publication title -
soil use and management
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.709
H-Index - 81
eISSN - 1475-2743
pISSN - 0266-0032
DOI - 10.1111/sum.12643
Subject(s) - straw , mineralization (soil science) , fertilizer , nitrous oxide , greenhouse gas , nitrogen , agronomy , zoology , chemistry , nitrogen cycle , environmental science , soil carbon , soil water , soil science , ecology , biology , organic chemistry
An increasing area of oilseed rape cultivation in Europe is used to produce biodiesel. However, a large amount of straw residue is often left in the field in autumn. Straw mineralization provides both carbon (C) and nitrogen (N) sources for emission of soil nitrous oxide (N 2 O), which is an important greenhouse gas with a high warming potential. Some studies have focused on soil N 2 O emissions immediately post‐harvest; however, straw mineralization could possibly last over winter. Most field studies in winter have focused on freeze‐thaw cycles. It is still not clear how straw mineralization affects soil N 2 O emissions in unfrozen wintertime conditions. We carried out a field experiment in northern Germany in winter 2014, adding straw and glucose as a source of C with three rates of N fertilizer (0, 30, and 60 kg N ha −1 ). During the 26 days of observation, cumulative N 2 O emission in treatments without C addition was negative at all N fertilizer levels. Straw addition produced –3.2, 11.2, and 5.0 mg N 2 O‐N m −2 at 0, 30, and 60 kg N ha −1 , respectively. Addition of glucose surprisingly caused –1.5, 74.6, and 165 mg N 2 O–N m −2 at 0, 30, and 60 kg N ha −1 , respectively. This study demonstrates that oilseed rape straw does not cause high N 2 O emissions in wintertime when no extreme precipitation or freeze‐thaw cycles are involved, and soil organic C content is low. However, N 2 O emission could be intensively stimulated, when both easily available organic C and nitrate are not limited and the soil temperature between 0 and 10°C. These results provide useful information on potential changes to N 2 O emissions that may occur due to the increased use of oilseed rape for biodiesel combined with less severe winters in the northern hemisphere driven by global warming.